Can't turn off central heating

[barca]

Dear forum
My problem is I can only turn the central heating off and on by the main switch in the airing cupboard
The program timer is Siemens RWB29 it all lights up I have just put in a new cell battery
Or do I need a new HSA2 or could it be the thermostat sitting next to the programmer
Any help would be good
Thanks

 

[DGT plumbing]

What is you set up?
Combi or traditional.

 

[barca]

Sorry It’s a traditional

 

[townfanjon]

If you turn your room stat and cylinder stat down does it go off

 

[DGT plumbing]

Do you have a tree way valve ?

 

[DGT plumbing]

*three

 

[barca]

No the thermostat doesn’t turn off and it’s a two way valve

 

[townfanjon]

Could you post some pics of your system, you would generally have 2 x 2 port valves

 

[barca]

Sure I will do that in the morning
I will take a photo of the 2x valves
Thanks

 

[Ian10261]

More than likely the 2 port is stuck open which means the microswitch inside is making the connection between the grey wire(permanent live) and the orange wire (switched live to the boiler).
You may get away with taking the actuator head of and moving the valve spindle manually back and forth to free it up but this will more than likely be just a temporary fix. A new valve is the way to go and i would suggest a system flush while your at it, as dirty primary water could well be the cause of the valve sticking open.

 

[barca]

Hope that helps